Diabetes is a disease in which the body does not produce or properly use insulin. Insulin is a hormone that is needed to convert sugar, starches and other food into energy needed for daily life. The American Diabetes Association estimates that there are over 18 million people in the United States alone, or 6.3% of the population, who have diabetes.
Diabetic neuropathies are a family of nerve disorders caused by diabetes. People with diabetes can, over time, have damage to nerves throughout the body. Neuropathies lead to numbness and sometimes pain and weakness in the hands, arms, feet, and legs. People with diabetes can develop nerve problems at any time, but the longer a person has diabetes, the greater the risk.
Diabetic neuropathies can be classified as peripheral, autonomic, proximal, and focal, each of which affects different parts of the body in different ways. The most common type is peripheral neuropathy, also called distal symmetric neuropathy, which affects the arms and legs. In particular, peripheral neuropathy causes either pain or loss of feeling in the toes, feet, legs, hands, and arms. Blisters and sores may appear on numb areas of the foot, and the loss of sensation in the feet means that such sores or injuries may not be noticed and may become ulcerated or infected. If foot injuries are not treated promptly, the infection may spread to the bone, and the foot may then have to be amputated.
Patients suffering from diabetes are also at increased risk for cardiovascular complications. Diabetes is believed to affect how the heart pumps blood through the body. Diabetes can change the chemical makeup of some of the substances found in the blood, which in turn can cause blood vessels to narrow or to clog up completely. Such circulation problems also increase the risk of foot ulcers, and as a result cardiovascular complications resulting from diabetes is another leading cause of lower-limb amputations in the people with diabetes.
Thus the nature of diabetes can result in nerve damage and/or diminished circulation in the extremities, such as the feet. This, combined with the normally high moisture environment of the foot and the often undesired barrier properties of certain stockings and shoes, and the normal friction created by foot movement (e.g., walking), can increase the problems suffered by such persons.
U.S. Pat. No. 5,724,836 to Green is directed to a sock stated to cushion and at the same time keep the wearer's foot cool and dry. The sock includes a breathable instep panel, a padded sole, and a transition zone located between the foot section and leg section. Despite the potential benefits of the sock, it is not intended for use with diabetic patients. Patients with poor circulation in the extremities can have significant swelling in their feet and legs. It can be difficult to put on and remove a sock like that of the '836 patent from a patient's swollen foot and/or leg region. In addition, a sock like that of the '836 patent can wrinkle or bunch about the foot of the wearer during normal movements and thus can also potentially irritate the skin of the wearer.